MSSQL, PHP4, Windows XP - unable to connect

Here is the setup:
Server:
-SQL 2000 SP3 on a win2k box
-Firewall set up to allow connections for all ports
ntwdblib.dll version 2.8.0 (newest)

Client:
XP Pro SP2
Apache 2.0.52
PHP 4.3.8.8
ntwdblib.dll version 2.8.0 (copied from server)
extension=php_mssql.dll uncommented

The code looks like this:

$dbinfo = mssql_connect($host,$user,$pass);
 $test = mssql_get_last_message();

 echo $test;

Here is the response when going to the page:

Also installed on the client machine is the SQL tools from the SQL 2000 CD. It can connect with the same username and password witihout problem.

Any other instance of similar problem that I have been able to find online has involved simply replacing the ntwdblib.dll file. This has not helped.

Does anyone have any suggestions?

If you read the User Notes on the manual , several cover this problem and give solutions.

I appreciate your help, and here's why it wasn't working:

For MS SQL, if you are going to use a port, you must use a comma instead of a colon: e.g. "myserver.mydomain.com,1433"
This particular computer was set up with minimal services running, which allowed mysql, php, apache, ftp, firewall, etc. to run. However, "TCP/IP NetBios Helper" was apparently necessary for PHP to connect to an SQL 2000 server.

And yet they claim that WINS and NETBios are redundant on W2K server??

go to firewall option

and open port 3306

then it works